A power system may comprise an internal combustion engine and an EGR system for recirculating a portion of the engine's exhaust flow back to an intake manifold. This portion of the exhaust flow is commonly referred to as EGR flow and is useful for reducing the concentration of oxygen available for combustion, thus lowering the combustion temperatures, slowing reactions, and decreasing nitrous oxides (NOx) formations. While, as just mentioned, EGR flow means the exhaust flow that is recirculated into the engine, fresh air flow, conversely, means the flow that is entering the power system from the atmosphere.
In some cases, the intake manifold needs to supply a precise ratio of EGR flow to fresh air flow, because too small of a ratio may cause an increase in NOx emissions, while too large of a ratio may cause an increase in soot emissions. To achieve both low NOx and soot emissions simultaneously, it is important that the ratio of the EGR flow to air flow be optimized and that also the ratio be consistent amongst all of the engine's cylinders. To do this, what is needed in the art is an EGR mixer that adequately mixes the EGR and fresh air flows.